Impact of coronary vasa vasorum functional structure on coronary vessel wall perfusion distribution

Abstract

Gö ssl, M., N. M. Malyar, M. Rosol, P. E. Beighley, and E. L. Ritman. Impact of coronary vasa vasorum functional structure on coronary vessel wall perfusion distribution. Am J Physiol Heart Circ Physiol 285: H2019-H2026, 2003. First published July 10, 2003 10.1152/ajpheart.00399.2003.-Noncoronary vasa vasorum have been described as networks of microvessels in the wall of arteries and veins. However, we have shown, using microcomputerized tomography (micro-CT) imaging methods, that porcine coronary vasa vasorum have a tree-like branching structure similar to the vasculature in general. In this study, we elucidate functional aspects of coronary vasa vasorum perfusion territories. Three pig hearts were injected with radiopaque Microfil via the coronary sinus to fill the left anterior descending coronary arteries (LADs) retrogradely at atmospheric pressure. In three other hearts, LADs were injected antegradely at 100-mmHg pressure via the left main carotid artery. Additionally, six LADs were injected in vivo with a suspension of 100-or 300-m-diameter microspheres before harvesting of the hearts and injection of the LADs with Microfil. All harvested LADs were scanned intact with micro-CT (20 m cubic voxels). The spatial density of vasa vasorum (no. of vasa/mm 2 ) was measured in 20-m-thick cross sections (at 0.4-mm intervals). Retrogradely injected LADs showed high and uniformly distributed vasa vasorum densities in the adventitia (means Ϯ SE; 5.38 Ϯ 0.09 vs. 3.58 Ϯ 0.1 vasa/mm 2 in antegradely prepared LADs; P Ͻ 0.001). Antegradely prepared LADs showed patchy distributed, low-vasa-vasorumdensity territories especially on the myocardial side of the coronary artery wall (epicardial density: 4.29 Ϯ 0.13 vasa/ mm 2 vs. myocardial density: 2.80 Ϯ 0.1 vasa/mm 2 , P Ͻ 0.001). Microembolization reduced vasa vasorum densities significantly (100-m-diameter microspheres: 3.26 Ϯ 0.07 vasa/mm 2 , P Ͻ 0.05; 300-m-diameter microspheres: 2.66 Ϯ 0.07 vasa/mm 2 , P Ͻ 0.001 vs. antegrade controls) and increased the size of low-vasa-vasorum-density territories. We conclude that coronary vasa vasorum are functional endarteries not connected via a plexus. This characteristic may have a significant impact on the spatial distribution of perfusion and drainage of the coronary vessel wall.intraluminal coronary artery pressure; microembolization; microcomputerized tomography VASA VASORUM HAVE BEEN DESCRIBED as a "network" or "plexus" of microvessels located in the vessel wall of arteries and veins responsible for nutrient supply to and drainage from the vessel wall (2, 9, 21, 24, 25). A recent study by our group (5) using microcomputerized tomography (micro-CT) showed, however, that the general structure of coronary vasa vasorum is "treelike," consistent with endarteries. Furthermore, we could show that despite the constrained topology of the space in which they proliferate, the hemodynamic characteristics of coronary vasa vasorum are surprisingly similar to that of the vasculature in general. Although several investigators (6,14,17) have sh...

Vasa Vasorum in Normal and Diseased Arteries

“…Under physiological conditions, the adventitial vasa vasorum and lymphatic vessels take up molecules that are transmitted from the blood to the adventitia by mass transport through the arterial wall. [9][10][11] Vascular injury at the luminal side of the vessel wall significantly impacts the adventitia by convection of soluble factors, microparticles and macroparticles, mediators such as products of oxidation, tissue cytolysis, and proteolysis from the intima to the adventitia by hydraulic conductance. 12 As a result, the adventitia becomes the primary early site for the vessel wall response to arterial injury, which includes myofibroblast migration into the vessel wall, 13,14 inflammatory cell accumulation, [15][16][17] and expansion of vasa vasorum.…”

Efeitos da remoção da túnica adventícia da aorta descendente em suínos

“…It is believed that the adventitial layer has a key role in the genesis and maintenance of vascular inflammation seen in aneurysms and atherosclerotic vascular disease 6,7 . The three-dimensional study of VV was made possible by micro-computed tomography studies 8,9 , as well as a better understanding of the anatomy and distribution by micro-arteriography. The adventitial VV connect to each other by means of a plexus, but behave like terminal arteries.…”

Ruptura dos vasa vasorum e hematoma intramural da aorta: um paradigma em mudança

“…In humans, arteries containing less than 29 cellular layers or less than 0.5 mm diameter do not present VV. 1,2 Thanks to microcomputerized tomography, tridimensional study of these vessels became possible, 3,4 as well as microarteriography have enabled a more thorough understanding of their anatomy and distribution 5 through the injection of a silicone polymer (Microfil ® , Flow Tech, U.S.). VV seem to play a fundamental role in the physiopathology of the three acute aortic syndrome entities: aortic dissection, intramural hematoma (IMH), and penetrating ulcer.…”